1. Field of the Invention
The present invention relates generally to a wireless communication apparatus and a wireless communication method for detecting an electric field intensity of a wireless channel.
2. Description of the Related Art
In recent years, for example, in a wireless communication system specified in, for example, IEEE 802.15.4, a preset wireless frequency band is divided into a plurality of wireless channels in predetermined band widths so as not to overlap each other. Any one of the wireless channels is selected, and wireless communication between ratio communication apparatuses is performed in the selected wireless channel.
In such a wireless communication system, there is a wireless communication apparatus having a function of transmitting/receiving data and a function of detecting the electric field intensity of a wireless channel for transmitting/receiving the data in order to continuously maintain good communication environments.
For example, Jpn. Pat. Appln. KOKAI Publication No. 2003-151062 discloses a wireless apparatus comprising a wireless unit configured to perform data communication, a control unit configured to read reception level output from the wireless unit using two channels of different frequencies, and a storage unit configured to store the read reception level. However, the apparatus has a problem in that the reception level cannot be detected while data is transmitted/received.
To address the problem, there is a wireless communication apparatus comprising two wireless units. One of the wireless units is used for data transmission/reception, and the other wireless unit is used for detecting the electric field intensities plurality of wireless channels in order to find a wireless channel whose communication state is excellent. In such a wireless communication apparatus, while one of the wireless units transmits/receives data, the electric field intensity of the wireless channel used for transmitting/receiving data is detected. Consequently, it becomes unclear whether the detection result of the wireless channel used is a result of detecting the electric field intensity accompanying transmission/reception of data, a result of detecting the electric field intensity of an interference wave, or a result of detection of both of the electric field intensities. That is, there is a problem in that, the electric field intensity for determining the communication state of the wireless channel used cannot be detected.
Further, it is considered that when one of the wireless units and the other wireless unit are synchronized and one of the wireless units is transmitting/receiving data, the electric field intensity of the wireless channel used is not detected. However, the data transmitting/receiving timing occurs at random. Consequently, there are problems in that the electric field intensity of the wireless channel being used cannot be periodically detected, and the detection result cannot be evaluated equivalent to the detection results of the electric field intensities of other wireless channels.